BOSTON – Lawyers for former Probation Commissioner John O’Brien are asking U.S. District Court Judge William Young to acquit their client, arguing that Young erred in his instructions to the jury and that the premise of the conviction was unsound.

On July 24, jurors convicted O’Brien and two former deputies, Elizabeth Tavares and William Burke III, of crimes associated with rigging the hiring system within the probation department to favor politically connected applicants.

Attorney Stellio Sinnis argued in a new motion filed Tuesday that Young had improperly laid out the government’s case “in logical progression” for the jury and “erroneously” told jurors that passing recommended names to interview panels was “questionable” and “highly questionable” in the case of a superior passing names to a subordinate.

Sinnis asked that if Young declines to enter an acquittal ruling, he should rule for a new trial.

During the months long-trial earlier this year, defense attorneys cast the hiring practices at the probation department as status quo, part of a system where court officers and other state employees receive jobs because they are sponsored by someone with political heft.

In Tuesday’s filing, Sinnis argued that the alleged scheme described at the trial, where Speaker Robert DeLeo was said to be a co-conspirator, differed from the scheme laid out in the indictment and evidence did not prove the alleged bribes were in exchange for any specific official act.

“Critically, the government did not present sufficient evidence of a link between the alleged gratuity and a specific official act,” Sinnis wrote.

The jury sided with prosecutors, determining that O’Brien ran a secret patronage system under the veil of a purportedly merit-based personnel process, manipulating the scoring of job applicants to ensure his choices rose to the top.

Driving at the foundation of the fraud case, Sinnis also said former Chief Justice of Administration and Management Robert Mulligan was well aware of political influence on hiring and prosecutors misconstrued O’Brien’s signature on hiring documents. Mulligan had the final sign-off on O’Brien’s appointments, and prosecutors argued he relied on O’Brien’s certification that the proper process had been followed.

“The Commissioner’s stamped signature on this line indicated that someone had posted the job, reviewed applications, interviewed applicants, conducted the proper records checks, and assembled the correct paperwork, not that he hired pursuant to the Trial Court Manual or had selected the “most qualified” candidate,” Sinnis wrote in the 41-page document.

He said, “At the time of the alleged conduct here, there was no statute or other regulation that gave the Massachusetts legislature or populace any reason to expect that probation officers would be hired in a certain manner or that those officers would be the “most qualified” under any metric. The statute in effect at the time gave the Commissioner the absolute appointment authority.”

Page 2 of 2 - Sentencing is scheduled for November and Young has tentatively scheduled a February trial for another set of charges that are similar to the ones jurors heard about over the course of the two-and-a-half- month trial.